While the incarnation was essential for our approach to God, something else was absolutely necessary, and that the accomplishment of redemption. Our having boldness to enter the holiest, the immediate presence of God, is by "the blood of Jesus."
Although the incarnation was, of necessity, before the work of atonement, in Hebrews 10 the blood is mentioned before the veil. There are many who teach that access to God is by the humanity of Christ, but God would have us to know that there could be no approach apart from the blood.
In the burnt offering, the blood was sprinkled on the altar round about (Lev. 1:5, 11), God indicating to us that from whatever view we might consider approach to Him, the blood of sprinkling was necessary. God will not have us before Him in communion or as worshippers unless it be on the ground of atonement.
Certain of the sin offerings had their blood poured out at the bottom of the altar, which surely signifies that our approach to God as sinners is founded on the blood of Christ. We could not be in God's presence without being cleansed from our sins, and it is "The blood of Jesus Christ His Son (that) cleanseth us from all sin" (1 John 1:7).
After the Lord Jesus had yielded up His spirit to God, the veil of the temple was rent in twain, from top to bottom; signifying that God had come out to meet men through the death of Christ; that the old system of Judaism, where there was no approach to God, saving for the High Priest once a year to do the work of atonement, was done away in Christ's death; and that there was now a way into the presence of God for man through the work of His Son on the cross.
The way of our approach to God as sinners is by a blood sprinkled mercy-seat (Rom. 3:25); the way of our approach for daily help is by way of the Throne of Grace (Heb. 4:15-16); and the way of approach for communion and worship is into the holiest by the blood of Jesus (Heb. 10:19).